Saturday, July 3, 2010

Bar Stools- Rungs

Rungs are important structural part of any chair, but even more so on a tall stool. The lengthened legs put increased leverage on the seat joinery, and the front rung serves as a footrest and as a mounting aid. I cut mine from 6/4 stock, as they need to be a full 1" x 1 1/4". I try to choose for the straightest grain on these parts.

The angles are found in the same manner as the seat backs. The portions already made are clamped up and traced.

The part is drawn.

Angles are found with the bevel gauge.

Same goes for the front legs.

Joinery is located directly from the leg.

My Veritas Sliding Bevel is one of my favourite layout tools. As far as I'm concerned, its cam lock is the only appropriate method for securing the blade on a tool of this nature. The blade is 1" wide, making tenon layout easy.

Nine stools, IKEA flat pack style:

Dry fit:


Thursday, July 1, 2010

Bar Stools- Working the Angles

The next part is the back seat strecher. This part determines the angles for the rest of the back joinery. I start with a full size drawing of the top of the seat. This is my first layout, I decided the seat looked too square, the front rail was lengthened by 2". Unfortunately I neglected to photograph the updated plan.

The back legs are angled inward. This splays the legs for a stable footprint, and gives the back a outward and upward look that is visually pleasing and physically comfortable. The part dimensions are taken directly from my drawing.

The back legs and seat rail are clamped together and traced to find the dimensions and angles for the seat back crest rails.

This is a photo of the way I determined the rung angle, but I used the same technique for the crest rails.

These parts will be curved, so they are milled from 8/4 stock.

The parts are dry assembled, and the profile of the leg is traced onto the crest rail. The top is tablesawn to the same angle as the leg. An arc is then drawn from a template, and bandsawn. The amplitude of this arc is 1/4".

Because the back of the leg is not parallel to the front, the bandsaw table is tilted to make that curve.

The bandsaw marks are removed at the edge sander.

Working from the full size drawings of the seat side and top, the side rails are cut. Having your knees slightly higher than your hips is important for long term comfort; this seat will rise 1/2" over it's length.

The front seat rails are cut next, and now I have a model to assemble and test for comfort.


Sunday, June 27, 2010

Bar Stools- Mortise, Taper, Mortise

Next I mill up the front legs. This is the last point at which lefts and rights are interchangeable. I select for the best colour and grain to be exposed and put sapwood and defects to the inside. Not only are they less visible there, but the two inside planes of the legs get tapered, so there is a good chance flaws will be sawn off. The bottoms are marked with the chosen orientation.

I don't use the Leigh FMT often, but I really like it for oddball joinery- angled and compound mortise and tenons, or for tenoning parts like bent laminated skirts that don't register properly for the tablesaw.

The mortises are cut in the legs, in the locations that aren't tapered- the seat and back support rails.

Next I make a taper jig. I've used commercial and homemade versions of the commercial hinged jig, but I find them fussy to setup. I can make a custom jig in less time.

I start with a scrap piece of plywood, a little longer than my part.

I draw the taper on the stock, put the cut line on the edge of the plywood, and screw down a fence and a rear stop. If the fence or the stop overhangs the plywood edge, I send it back though the tablesaw to trim it flush.

The jig is then sent through the saw, which hasn't been changed since first cutting the plywood base. I am tapering both inside faces, it is important to do them in the correct order. First they are cut one mortise down, the other to the blade. Next, one mortise is up, the other to the blade. Doing it the other way around results in an already tapered face registering against the jig bed, throwing off the angle of the second face. The front legs are getting the same amount of taper on each side, but the leg itself is rectangular by 1/8" of an inch. A shim is used to compensate.

The saw pushes the part against the stop, I am comfortable leaving it loose on the jig, but if you like a hold down clamp like a De-Sta-Co can be screwed to the jig fence and used to hold everything secure.

The leg is rotated and tapered on the second face.

Next I taper the back legs. Using the same jig, I send the left legs through.

Because of the shape of the legs, the jig needs to be altered to cut the rights.

I would highly reccomend the use of hold downs for this process. I didn't, and the procedure was a little dicey. The leg need to be held down against the jig bed and the side fence, the jig needs to be held tight to the tablesaw fence, the whole thing needs to be slid past the blade while cutting forces are wanting to push the leg away from the end stop.

Now that the legs have been tapered, the mortises for the rungs can be cut, perpendicular to the face of the leg.


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I'm a woodworker on the Canadian prairie.